1. Technical Field
The present invention relates to pharmaceutical compositions for enhancement of libido. The present invention also relates to methods of enhancement of libido in humans and animals.
2. Background Art
Many men and women suffer from a low libido, sexual dysfunction (including erectile dysfunction), or low sexual desire. As men and women age, sexual desire and function can decrease. Other factors can lead to low libido including stress and anxiety, depression, mental disorders, diseases (diabetes), obesity, high blood pressure, high cholesterol, medication side effects (such as from SSRI-type antidepressants or antihypertensives), low testosterone levels (as may be the case in swine and dairy cows), and low dopamine levels in the brain.
There are several different treatments available for low libido or sexual dysfunction. Sildenafil (VIAGRA®, Pfizer) is used to treat erectile dysfunction by inhibiting c-GMP-specific phosphodiesterase type 5 (PDE5) to regulate blood flow. Sildenafil for the treatment of impotence is described in U.S. Pat. No. 6,469,012 to Ellis, et al. Sildenafil must be administered an hour prior to sexual intercourse.
There have been negative side effects of using sildenafil, including sudden hearing loss, headache, flushing, impaired vision, severe hypotension, myocardial infarction, and stroke.
U.S. Pat. No. 4,087,524 to Grunwell, et al. discloses derivatives of androst-4-en-19-ol which are useful in enhancing the libido and related psychic attitudes in primates.
CA 2498267 to Dudley discloses a transdermal hydroalcoholic testosterone gel formulation that overcomes the problems associated with other testosterone delivery mechanisms by providing, among other things, a desirable pharmacokinetic hormone profile with little or no skin irritation. The gel may be used as a method of improving sexual performance, including treating erectile dysfunction, and increasing libido by increasing testosterone levels in men. In addition, the gel may be used in conjunction with pharmaceuticals aimed at treating erectile dysfunction, such as sildenafil (VIAGRA®, Pfizer), to enhance their effectiveness.
U.S. Pat. No. 6,734,186 to Maw, et al. discloses a method of treating a female suffering from FSD (female sexual dysfunction), in particular FSAD. The method comprises delivering to the female an agent that is capable of potentiating cAMP in the sexual genitalia; wherein the agent is in an amount to cause potentiation of cAMP in the sexual genitalia of the female. The agent may be admixed with a pharmaceutically acceptable carrier, diluent or excipient.
U.S. Patent No. 2009/0202662 to Fouche, et al. discloses a process for the production of a substance or composition for the therapeutic or prophylactic treatment of erectile dysfunction or the enhancement of libido in a male human or animal subject that includes the step of formulating the substance or composition from at least one of plant material and an extract of plant material of at least one plant species of the family Geraniaceae.
Cherkasov, et al. (J. Med. Chem. 2005, 48, 3203-3213) describes nonsteroidal ligands for human sex hormone binding globulin. Models were based on 5α-dihydrotestosterone (DHT) and the nonsteroidal ligands had the ability to displace DHT.
Kumar, et al. (Journal of Steroid Biochemistry & Molecular Biology 71 (1999) 213-222) teaches dose response of ventral prostate (VP) and levator ani (LA) to T, dihydrotestosterone (DHT), 19-nortestosterone (19-NT), 7a-methyl-19-NT (MENT), 7a-cyano-19-NT (CNNT), and 7a-acetylthio-19-NT (ATNT) in castrated rats. The most potent androgenic steroid (VP response) was MENT followed by T, DHT, 19-NT, ATNT, and CNNT. On the other hand, the order of anabolic potency (LA response) was MENT>19-NT>T>DHT>ATNT>CNNT.
There remains a need for an effective treatment for low libido and sexual enhancement. There further remains a need for new steroid treatments that can affect low libido and sexual enhancement, as well as treatments for breeding synchronization in animals.